Method for operating a domestic refrigeration appliance, in which a misting rate is adapted, and domestic refrigeration appliance

ABSTRACT

A domestic refrigeration appliance has a separate storage area in an internal space into which foodstuffs, forming storage items, can be introduced. A liquid fluid can be introduced in the storage area independently of the internal space. For keeping the storage items fresh in the storage area a first operating mode and a storage mode, different therefrom, can be carried out. In the storage mode an aerosol mist generated by a misting device of the domestic refrigeration appliance is introduced as a fluid, and a misting rate of the aerosol mist during the storage mode is matched to a setpoint misting rate in dependence on at least one misting device-specific influencing parameter and/or a fluid-specific influencing parameter and/or a storage area-specific influencing parameter. There is also described a domestic refrigeration appliance.

The invention relates to a method for operating a domestic refrigeration appliance in which foodstuffs as storage items can be introduced in a separate storage area formed in an internal space. A liquid fluid can be introduced in the storage area independently of the internal space. Moreover, the invention relates to a domestic refrigeration appliance with an internal space in which a partial volume is formed as a separate storage area into which foodstuffs may be introduced. The domestic refrigeration appliance comprises a humidifying device, an ambient humidity which is different from the remaining internal space being able to be adjusted thereby in the storage area.

Domestic refrigeration appliances are known from the prior art, such as for example a refrigerator which comprises an internal space for introducing foodstuffs. This internal space is generally delimited by an internal container and closed by a door on the front face. Cool air is generated in the internal space, said cool air being produced by a refrigerating circuit in which heat is discharged from the internal space. In the internal space a storage area is formed separately therefrom, said storage are also being configured for receiving foodstuffs, wherein it is possible to introduce a fine water mist here, wherein as a result the storage quality of these fresh foodstuffs is positively influenced. Thus in the case of fresh fruit and vegetables, the product quality is maintained for a particularly long time by humidifying during storage. Moreover, an accelerated cooling of these foodstuffs is carried out by such a humidifying, by means of a water mist.

Fruit and vegetables are products which still have an active metabolism even after having been harvested. Transpiration and respiration processes result in the loss of valuable nutrients, as well as in the loss of fresh mass due to the loss of moisture.

By suitable storage conditions, these processes may be reduced or retarded. The higher the storage temperature at the freezing point of the respective product, the lower the nutritive losses, since metabolic processes almost completely come to a standstill. To this end, by active humidifying during storage, freshly stored foodstuffs may be cooled by evaporative cooling which also ensures that the preservation of the product quality is improved.

Transpiration losses may be primarily avoided by the equilibrium moisture content of the storage items being kept in the storage environment. For example, this is achieved by corresponding packaging or protected storage in sealed storage boxes. This is already implemented in refrigerators in special vegetable trays with humidity control.

Additionally, there are systems which attempt to keep the air humidity content high and thus the transpiration losses of stored fruit and vegetables low, by evaporative humidifying inside the vegetable tray, by rewetting or the active misting of water in the vegetable tray. Systems for active humidifying are additionally known from the food retail industry. Active humidifying is carried out in the product presentation of unpackaged goods in order to reduce moisture losses of the product. In this case, within the function of keeping products fresh in domestic refrigeration appliances the systems are always limited by the underlying cryogenic system and the dependency of the loading of the corresponding storage areas. Thus with so-called no-frost systems, a very high level of dehumidifying takes place which potentially may have a negative effect on the storage of fruit and vegetables. On the other hand, there are systems in which the correct functionality is only provided with a high level of loading and thus the introduction of a high level of humidity.

Previous systems in domestic refrigeration appliances are only able to maintain the given product status within the cited limits. An improvement in the product quality in the sense of an additional protective function or in the sense of restoring freshness which has already been lost is not possible.

Domestic refrigeration appliances in which such a separate storage area is configured in an internal space are disclosed in DE 10 2009 029 139 A1 and DE 10 2009 029 141 A1.

It is the object of the present invention to improve the process of keeping of fresh foodstuffs fresh in a storage area in an internal space of a domestic refrigeration appliance.

This object is achieved by a method and a domestic refrigeration appliance as claimed in the independent claims.

In a first feature of the invention, in a method for operating a domestic refrigeration appliance it is provided that foodstuffs as storage items can be introduced in a separate storage area formed in an internal space. Liquid fluid as droplets can be introduced in the storage area independently of the internal space. This means that fluid may be introduced into the partial volume which is formed by the storage area, without such a fluid being introduced into the remaining volume of the internal space which is present in addition to the storage area. Thus in terms of structure and components the basic assumption is made that the fluid is also introduced into the storage area in specific phases and this is carried out independently of the remaining internal space.

Preferably it is provided that an aerosol mist is introduced as fluid. This is particularly advantageous for the wetting of storage items with the fluid and, for example, a substantial advantage relative to an introduction of a water gas which is different therefrom. The aerosol may then be absorbed by the storage items for improving the process of keeping said items fresh.

An essential idea of the invention may be seen to be that for keeping the storage items fresh in the storage area a first operating mode and a second operating mode different therefrom, namely a storage mode, can be carried out. This means that the domestic refrigeration appliance is configured such that at least these two different operating modes may be provided and implemented for keeping the storage items fresh. Thus these operating modes may, in particular, be implemented selectively and thus the storage items kept fresh individually.

In this specific storage mode, an aerosol mist generated by a misting device of the domestic refrigeration appliance is introduced as fluid into the storage area and a misting rate of the aerosol mist during the storage mode is matched to a setpoint misting rate in dependence on at least one misting device-specific influencing parameter and/or in dependence on a fluid-specific influencing parameter and/or in dependence on a storage area-specific influencing parameter. Such an embodiment is improved by keeping the storage items fresh, therefore, since it takes place in a substantially adapted and appropriate manner and even over a relatively long time period and thus over a relatively long storage time it is also possible to provide a relatively uniform misting rate per time interval and/or surface unit of a floor of the storage area and/or volumetric unit of the storage area. It substantially facilitates the process of keeping the storage items fresh.

Thus it is provided, in particular, that when implementing the storage mode a respective current actual misting rate of the aerosol mist is adapted to a setpoint misting rate, when the actual misting rate of the aerosol mist deviates from the setpoint misting rate or a tolerance interval thereof, as a result of a misting device-specific influencing parameter and/or a fluid-specific influencing parameter and/or a storage area-specific influencing parameter.

Since the aforementioned deviation, which occurs relative thereto in practice and due to the practical reasons, may occur even with relatively long storage times, a compensation thereof is carried out by means of the invention so that the storage items may also be kept fresh over a very long period of time in an improved manner.

Preferably, the setpoint misting rate is constantly predetermined over the entire storage time of the storage items in the storage area. The adaptation is carried out, in particular, such that the entire storage time of storage items is divided into at least two time intervals, in particular of equal length, and a misting rate in a first time interval of the storage mode is within a tolerance interval of a misting rate in a second time interval of the storage mode and, in particular, both misting rates in the respective time intervals are also located in a tolerance interval around the setpoint misting rate. By means of such an embodiment, in a particularly advantageous manner the actual misting rate is kept practically constant during the entire storage time in the storage mode, which effects a substantially improved procedure for keeping the storage items fresh, even with relatively long storage times which last over several days, in particular more than ten days.

Preferably, the first time interval and the second time interval, with a storage time of at least two full days, are characterized in that in each case the time intervals are one day. These time intervals are configured practically the same with regard to influencing factors and the adaptation of the misting rate may be carried out very consistently.

Preferably, it is provided that the misting rates in the time intervals are set with values of between 0.4 g and 0.6 g per 100 cm² during the storage mode according to at least one misting device-specific influencing parameter and/or a fluid-specific influencing parameter and/or a storage area-specific influencing parameter. This means that with regard to the quantity of fluid and/or the quantity which is introduced as aerosol mist, the aforementioned tolerance intervals are kept in the region of between 0.4 g and 0.6 g even over a relatively long storage time, even if specific influencing parameters might change the actual misting rate relative thereto.

Preferably, this mist quantity and thus the aerosol mist quantity is set between 0.4 g and 0.6 g per 100 cm², in 15 to 20 discharge cycles in the storage area with cycle times of between 55 seconds and 65 seconds and the number of discharge cycles and/or the duration thereof are set during the storage mode, according to at least one misting device-specific influencing parameter and/or a fluid-specific influencing parameter and/or a storage area-specific influencing parameter. Thus it is achieved by this advantageous embodiment that when this quantity of aerosol mist is not discharged in a single discharge cycle but in several discharge cycles, the number may be varied in order to be able to react in a very appropriate manner to the given situation during a time interval in a storage time and, therefore, to be able to provide in a very appropriate manner this desired quantity of aerosol mist which may be optionally adapted. Even in these multiple cycles this permits a more consistent adaptation over quite specific cycle time intervals, so that the setpoint misting rate is extended over time and not suddenly introduced, so that undesirably high fluctuations in the misting rate and thus also in the quantity of aerosol mist present in each case and viewed over time, are avoided. This is very advantageous for keeping the storage items fresh over relatively long storage times.

The misting rate is adapted early during the implementation of the storage mode according to a loading quantity of the storage area with specific storage items and/or a total volume of the storage area as a storage area-specific influencing parameter. As a result, undesired deviations from the setpoint misting rate may also occur due to situations, which are then established and in turn corrected in a very appropriate manner.

It may also be provided that the misting rate is adapted during the implementation of the storage mode according to the temperature of the fluid to be misted and/or a temperature alteration of the fluid to be misted and/or a temperature in the surroundings of a tank comprising the fluid to be misted and/or a temperature alteration of a tank comprising the fluid to be misted as fluid-specific influencing parameters. These respective current temperature values or temperature alteration values, which may also be taken into account from the past or estimated for the future according to current values or respective values in the past, result in a further finely adjusted and thus more appropriate adaptation of the misting rate so that even in this case over a lengthy, relatively long, storage time a very uniform misting rate is present in practice. This also facilitates the procedure of keeping very different foodstuffs fresh over a very long storage time.

Preferably, it is provided that the misting rate is adapted during the implementation of the storage mode according to a filling height of the fluid to be misted in a tank of the domestic refrigeration appliance and/or depending on a water hardness of the fluid as a filling-specific influencing parameter. Moreover, by these advantageous embodiments quite specific parameters are taken into account, therefore, which may lead to undesired alterations of the actual misting rate at least over a lengthy operating period of the domestic refrigeration appliance and in location-specific circumstances, so that by means of this advantageous embodiment already a preventative reaction may be made or an immediate reaction may be made to an undesired deviation of the misting rate.

Preferably, it is provided that the misting rate is adapted during the implementation of the storage mode according to a total operating time of the misting device as a misting device-specific influencing parameter. Since the generated misting rates may also drop here, observed over several storage modes and over the entire period of use of the misting device from the initial set-up, this is also monitored and then as a result of specific measures, in particular controlled via a control unit, an adjustment of the operation of the misting device may take place, so that the actual misting rate corresponds once again to the setpoint misting rate or may be set in a defined manner at least within a tolerance interval around the setpoint misting rate.

Preferably, the misting rate is adapted during the implementation of the storage mode according to a service life of a component, in particular an evaporator, of a refrigerating circuit of the domestic refrigeration appliance.

The introduction of the aerosol mist preferably takes place according to the type and/or quantity and/or position of the storage items in the storage area, which at times are at least locally limited in a storage area zone. Also, the current loading of the storage area with specific storage items is reacted to in a manner which is very appropriate to the situation, so that it may be prevented that too little aerosol mist or too much aerosol mist or aerosol mist in an undesirable quantity is brought into undesired storage area zones. By means of this embodiment, the aerosol mist is no longer introduced generally into the storage area at a fixedly predetermined point but aerosol mist is introduced very specifically and only at preferred points. In particular, it is provided that the storage area comprises a plurality of points via which the aerosol mist may be introduced, so that these points may be used individually in order to introduce the aerosol mist.

Preferably, the storage mode is only activated when the storage area is closed. By means of this embodiment, the energy-efficient operation of the domestic appliance is taken into account. Moreover, preferably when the storage area is open, no such fluid introduction is provided, for example by introducing a mist. A user is thus able to observe the storage area and remove the storage items located therein unhindered. In addition, undesirable wetting of a hand or a different limb of the user is prevented.

Preferably, for keeping the storage items fresh in the storage area, a refreshing mode is carried out as a first operating mode, in which the introduction of the fluid in the storage area is set according to a mass of the storage items in comparison with the fresh mass thereof and, as a result, the mass of the storage items is increased. In this feature of the invention, therefore, in a manner to be particularly highlighted, a process is carried out, namely the refreshing mode is completed, by means of which it is possible to alter the mass of the storage items. In this connection, it is not to be understood by such an alteration to the mass that the applied fluid remains on the surface of the storage items and is effectively considered as additional separate mass elements in this connection, but that the fluid penetrates into the storage items, by the storage items absorbing this fluid and being in turn effectively refreshed again by cytological processes, and, as a result, the fluid increases the individual basic mass. As a result, therefore, effectively an active cytological process of the storage items is initiated, said process being carried out by the storage items themselves so as to be refreshed by the application of the corresponding fluid, which determines the fluid introduction. This preferably takes place by the storage items again reaching their original initial freshness and thus the fresh mass which was present when the storage items were introduced into the storage area.

Preferably, the refreshing mode is provided by a misting phase in which the time period for the active introduction of fluid lasts between 1 minute and 60 minutes, preferably between 2 minutes and 45 minutes. In this misting phase, which thus represents in terms of time a partial phase of the refreshing mode, the ambient humidity is actively altered by introducing fluid into the storage area.

Preferably, the refreshing mode is implemented by a misting phase in which the introduction of fluid takes place in a clocked manner. This means that the active introduction of fluid does not take place continuously in a single phase but alternately active fluid is introduced in an active partial phase and in a subsequent deactive partial phase, an interval pause, the introduction of fluid is deactivated, wherein this sequence of the partial phases may be repeated multiple times. The active partial phases are then in total preferably between 1 minute and 60 minutes.

It may be provided that this clocked procedure is carried out such that the time durations of the two partial phases are always the same. However, it may also be provided that all of the active partial phases have the same time duration and the deactive partial phases have other similar time durations. Similarly, it may be provided that the time durations of at least two active partial phases are different from one another and/or the time durations of at least two deactive partial phases are different from one another.

It may be preferably provided that the time durations of the deactive partial phases are in total between 1 minute and 50 minutes, in particular between 4 minutes and 45 minutes.

Preferably, the time duration of an active partial phase, when carried out in a clocked manner with a plurality of active partial phases, may be between 30 seconds and 3 minutes, in particular between 1 minute and 2 minutes. It may be provided that the time duration of a deactive partial phase, when carried out in a clocked manner with a plurality of deactive partial phases, is preferably between 30 seconds and 3 minutes, in particular between 1 minute and 2 minutes.

Preferably, the refreshing mode is predetermined by a regeneration phase carried out after the misting phase, wherein the regeneration phase lasts between 5 minutes and several hours, in particular 24 hours. In the regeneration phase, the fluid introduced in the misting phase is actively absorbed into the storage items. By such a specification of the refreshing mode in a misting phase and a regeneration phase, the recovery and/or reprocessing of the storage items with regard to reaching the original fresh mass is substantially facilitated. The state of freshness of the storage items is particularly advantageously influenced and achieved thereby, which keeps the consumption quality of the storage items particularly high, even after a relatively long storage time.

Preferably it is provided that a storage mode and/or a hygienization mode is implemented after the refreshing mode.

In the hygienization mode, additives which have an anti-bacterial action are added to the fluid introduced into the storage area for adjusting the fluid introduction. As a result, undesirable contaminants or processes which promote the rapid deterioration of the storage items are prevented or at least considerably retarded.

Preferably, the hygienization mode lasts between 1 minute and 2 hours, and at least one of the additives: table salt, ozonated water, electrolyzed water, hydrogen peroxide, active chlorine, active oxygen, aldehyde, alcohol or organic acid is added to the fluid. For example, citric acid or ascorbic acid or acetic acid or a preservative such as sorbic acid or benzoic acid may be cited as organic acids.

Moreover, the invention relates to a domestic refrigeration appliance comprising an internal space in which a partial volume is configured as a separate storage area. Foodstuffs are able to be introduced into this storage area. The domestic refrigeration appliance also comprises at least one humidifying device by which a fluid may be introduced into the storage area in a different manner from the remaining internal space.

The humidifying device is configured such that, for keeping the storage items fresh in the storage area, a storage mode is able to be implemented in which the fluid introduction in the storage area is able to be set according to the storage items.

Additionally or alternatively, it may be provided that the humidifying device is configured such that, for keeping the storage items fresh in the storage area, a refreshing mode is able to be implemented in which the fluid introduction in the storage area is able to be set according to a mass of the storage items, in comparison with the fresh mass thereof, and as a result, the mass of the storage items is increased.

Additionally or alternatively, it may also be provided that the humidifying device is configured such that, for keeping the storage items fresh in the storage area, a hygienization mode is able to be implemented in which a growth-inhibiting additive is added to the fluid which is introduced for applying onto the storage items.

In this connection, domestic refrigeration appliances may be configured for the aforementioned individual method features. However, a domestic refrigeration appliance which takes into account at least two, in particular all, of the aforementioned different method features of the invention may also be configured.

In the storage area of the domestic refrigeration appliance, therefore, in particular a fine water mist is introduced as a fluid, for example via a cited ultrasonic nebulizer, for the purpose of the storage and/or regeneration and/or hygienization of foodstuffs. In this case water, such as mains water which is also suitable for consumption, may also be used. Preferably, cooled water is used.

In the storage area, it is provided, in particular, that the storage items do not come into contact with condensate present on the storage area floor or the mist and/or film of liquid deposited there. In this connection, it may be preferably provided that the storage area floor is uneven, for example having a wave structure or a supporting grid. By means of this embodiment, the storage items are prevented from being undesirably immersed in this liquid fluid collected on the floor side so that processes, such as for example the rotting of the storage items, may be prevented.

Preferably, in the storage mode in which humidifying and storage takes place, the introduction of the water mist as fluid is adapted in terms of quantity and/or frequency and/or duration to the type of product and the product state. Moreover, the loading, the structure of the storage system, in particular the sealing and the gap size, and the frequency of the opening of the storage area by a user and also the cryogenics used in the domestic refrigeration appliance, such as for example the start-up of a compressor or the operation of a fan, may be additionally or alternatively taken into account for the specific mode of operation of the storage mode in this case. Therefore, in this connection device-specific parameters may also be taken into account in order to refine and specify further the storage mode.

In this case it may be provided that the control may take place in a predefined manner, optionally also independently of the actually stored foodstuffs, via a humidity sensor and/or a temperature sensor and/or a condensation sensor or by preselection of the stored quantities and the storage items, by the user by specifying on the device electronics. Depending on the storage items, additionally an adaptation of the temperature level in combination with the misting system may be provided in order to ensure the product quality, even in a storage atmosphere of very high air humidity.

In a preferred method in the storage mode, after opening the storage area and storing the goods and/or the product and/or the storage items therein, optionally an activation of the additional humidity is carried out if required. In this connection, the appliance temperature and compartment temperature may be adapted, for example between greater than 0° C. and 4° C. This method may also be provided when closing the storage area.

It may also be provided that the storage mode is individually started by the user or runs completely automatically. Semi-automatic running may also be provided. In this embodiment, depending on specifically perceived and detected user behavior, the automatic starting of the storage mode may subsequently take place.

Therefore, the storage mode may run as an automatic and/or parameter-controlled program. In this connection, due to the automatic or at least semi-automatic sequence, the type of foodstuffs, for example a leaf vegetable or root vegetable or berry fruit, etc. may be taken into account. The quantity of the foodstuffs stored therein and/or the type of loading, such as for example a mixed loading with fruit and vegetables or a loading only with fruit or only with vegetables, may be taken into account additionally or alternatively.

Preferably, the storage mode starts after the storage area is closed, wherein the parameter values which have already been specified above may be advantageous here.

In the storage mode, optionally it may also be provided that a fan is subsequently operated after the misting, whereby the surface of the foodstuffs or surfaces of the storage area may be dried out.

An ionization and/or ozonization of the storage atmosphere may be provided as additional functions in the storage mode. Also, an air filtration may take place for specifically removing or adding odors, as for example may be the case by photocatalysis or by active carbon. Moreover, ethylene scavenging may take place, for example by KMnO₄. It is also possible for an exposure to ultraviolet light to be carried out. Blue light and/or red light may also be applied for maintaining the photosynthesis activity and in this connection corresponding light radiation may be provided in the storage area. All these aforementioned additional functions may be provided individually or in any combination. Also in this case, therefore, an at least single activation of the additional function provided may be carried out separately during the storage mode for a quite specific time period. Also, a repeated and thus pulsed implementation of at least one such additional function may be provided. Moreover, in this case the type and/or the duration and/or the time at which an additional function is activated, may be implemented according to the parameters of the storage area and/or the parameters of the introduced storage items already cited above.

Further features of the invention are disclosed in the claims, the figures and the description of the figures. The features and combination of features cited above in the description and the features and combination of features cited hereinafter in the description of the figures and/or shown separately in the figures are not only able to be used in the respectively provided combination but are also able to be used in other combinations or separately without departing from the scope of the invention. Thus embodiments of the invention which are not explicitly shown and explained in the figures but are revealed and able to be produced by separate combinations of features from the described embodiments are also to be regarded as encompassed and disclosed. Furthermore, embodiments and combinations of features which therefore do not have all of the features of an originally formulated independent claim are also regarded as disclosed.

Exemplary embodiments of the invention are described in more detail hereinafter with reference to the schematic drawings. The single figure shows a perspective view of an exemplary embodiment of a domestic refrigeration appliance according to the invention.

In the figure a domestic refrigeration appliance 1 which, for example, may be a refrigerator is shown in a schematic view. The domestic refrigeration appliance 1 comprises a housing 2 which surrounds an internal container 3. The internal container 3 defines with its walls an internal space 4 in which foodstuffs may be introduced for storage and preservation. Cold air is introduced into the internal space 4, said cold air being provided by a refrigerating circuit 5 provided schematically with the reference numeral. The refrigerating circuit 5 may comprise, for example, a compressor which is arranged in a machine chamber. Moreover, an evaporator which is arranged in the internal space 4 or at least thermodynamically coupled thereto may also be provided. The refrigerating circuit 5 may also have a condenser which is preferably arranged outside the internal container 3, in particular in a rear region of the housing 2.

In the exemplary embodiment, the domestic refrigeration appliance 1 comprises a storage area 6 which, although it is arranged in the internal space 4, is separated by a partition 7. The partition 7 thus divides the internal space 4 into a partial volume 8 and the storage area 6. The storage area 6 also comprises a drawer 9 into which foodstuffs may also be introduced.

The domestic refrigeration appliance 1 is designed with its refrigerating circuit 5, so that different levels of ambient humidity may be set in the partial volume 8 and in the storage area 6. The domestic refrigeration appliance 1 may, for example, be a no-frost appliance.

Preferably, in this connection the storage area 6 may be a compartment in which, in particular, temperatures of between greater than 0° C. and 4° C. are set. In specific embodiments, the temperatures in the remaining partial volume 8 may be slightly higher and may also be set by the user.

The internal space 4 and thus also the storage area 6 are able to be closed on the front side by a door 10.

The domestic refrigeration appliance 1 also comprises the humidifying device 11 which is also provided merely symbolically with a reference numeral. The humidifying device 11 is designed to bring sufficient moisture into the storage area 6. To this end, it may comprise a blower and/or fan otherwise present. Moreover, an air duct system is provided. In particular, the humidifying device 11 comprises a container and/or a tank into which water, in particular as fluid, is introduced. The humidifying device 11 also preferably comprises at least one further container into which an additive is introduced. This may then be mixed with the water from the tank for carrying out a hygienization mode and then introduced into the storage area 6 as mist or vapor.

The humidifying device 11 also comprises a unit, in particular a misting device, by means of which this fluid may be misted or evaporated. In this connection, it may be provided that this unit is an electric heating unit or a low pressure atomizer or a rotating disk and thus a rotary atomizer. Preferably, it is provided that this unit is an ultrasonic nebulizer or membrane nebulizer. The mist produced thereby is conducted by means of a duct into the storage area 6, wherein small inlet openings are arranged to this end at specific positions, the mist being conducted via said openings into the volume of the storage area 6.

The humidifying device 11 also comprises a control unit, in particular a control and/or evaluation unit, by means of which the control of the ambient humidity in the storage area 6 is regulated. In this connection, a sensor or a plurality of sensors may also be provided, said sensors detecting information about parameters of the storage area 6 and/or the introduced storage items and delivering said information to the control unit, wherein the control is carried out according to this information. In this connection, at least one temperature sensor and/or at least one humidity sensor and/or at least one weight sensor and/or a sensor for detecting the type and/or the freshness state of the introduced storage items may be provided.

In the exemplary embodiment it is provided that the domestic refrigeration appliance 1 with its humidifying device 11 is configured to implement a storage mode and a refreshing mode and a hygienization mode.

Foodstuffs in the form of vegetables and fruit after harvest discharge moisture to the surroundings, until a product-specific ambient humidity has been set. As a result, these food products lose fresh mass. The products become limp. If the relative air humidity in the storage area 6 is adjusted according to the equilibrium moisture content of the stored storage items, the loss of humidity may be reduced. Other types of vegetables, such as for example onions, require a relatively low air humidity which, for example, is 65% rH. Other vegetables or fruit require a relatively high air humidity which is greater than or the equal to 90% rH, in particular between 90% rH and 95% rH. For active humidity control the storage compartment and/or the storage area 6 comprises a system in which different operating modes may be set for keeping the storage items fresh. In particular, four different operating modes may be supplied here. It is provided here that the first operating mode is a refreshing mode in which in a relatively short time a very high level of mist is input and thus a very high level of aerosol mist is introduced. A second operating mode is the storage mode in which a quite specific adaptation is carried out relative to the quantity of the aerosol mist and the temperature and the surrounding humidity.

A third operating mode for keeping the storage items fresh is a drying mode. In this drying mode, no mist is produced. A fan of the misting device, optionally depending on a sensor, for example a humidity sensor, transports air from the internal space 4, which preferably is a refrigerator space, into the storage area. A corresponding air volume escapes via openings in a cover of the storage area 6 or optionally through leaks between the cover and a drawer of the storage area 6. The air transported into the storage compartment and/or the storage area 6, is dependent on the selected cryogenics of the domestic refrigeration appliance and in this connection whether it is a so-called no-frost appliance or a static appliance. Moreover, the relative air humidity of the transported air also depends on the refrigerating cycle of the domestic refrigeration appliance which means that this is dependent on whether the refrigerating circuit is active or inactive and/or how long the refrigerating circuit is active and how long it is inactive. If these states are observed during the operation of the fan, in the storage area 6 the air humidity may be reduced relative to a further third operating mode, namely a neutral mode. In the drying mode, the fan may be operated synchronously with the running time of the refrigeration compartment or even asynchronously. As a result, depending on the refrigerator, air containing different levels of relative humidity may be introduced into the storage area 6. It is also possible that a control is carried out according to the relative air humidity in the storage area 6 or even in the refrigeration compartment.

In the aforementioned fourth operating mode for keeping the storage items fresh, the neutral mode, the system is in standby mode, and in standby mode the fan does not run. The storage area 6 is subjected to conditions which are predetermined by a superordinate control of the domestic refrigeration appliance in which the storage area 6 is located.

In the aforementioned storage mode, the misting rate may be set by a user. The misting rate varies for different foodstuffs, such as fruit or vegetables, so that according to the storage items the misting rate which is adapted thereto may be set individually. Thus, for example, herbs or salads require a misting rate of approximately 10 g per day up to 12 g aerosol mist per day for a specific volume of, for example, 23 liters of a storage area 8 and/or a floor surface of the storage area 8 of approximately 0.13 m². Fruit or mushrooms require in this case a lower misting rate which, for example, is 2 g per day.

The quantity of mist discharged into the storage area 6 in the case of a relatively long storage time which is several days, preferably more than ten days, may in particular be introduced uniformly over the stored products and/or the product surface. The quantity of mist introduced into the storage area 6, in particular aerosol mist, is kept as uniform as possible over the storage time.

The misting rate required for the storage compartment and/or the storage area 6 may preferably be adapted according to the loading quantity and also the volume of the storage area 6. After a relatively short time, for example after one to two minutes, the aerosol mist is deposited on the foodstuffs, amongst other things. Therefore, the dimensioning of the storage area 6 and also the droplet size of the aerosol mist are parameters which preferably have to be taken into account in the control of the misting device and the fan for transporting the generated aerosol mist, with regard to a uniform distribution of the mist which is introduced. It is possible for these influencing parameters to have been previously determined and stored as reference values in a control unit, so that the desired quantity of the mist and the distribution is implemented as required and according to the situation, and a misting rate which is adapted very individually to these influencing parameters is produced. Therefore, the current actual misting rate is compared with a setpoint misting rate and in the case of an undesired deviation, in particular with a deviation outside a tolerance interval which is also in turn predeterminable, a corresponding adaptation takes place immediately. It may also be provided that such an undesired deviation is already prevented in advance, wherein by a corresponding detection of parameter values a possible occurrence of an actual misting rate outside the tolerance interval for a setpoint misting rate is avoided.

For hygiene reasons, and thus in order to halt bacterial growth on the storage items, the introduction of the aerosol mist is preferably carried out at intervals and thus in corresponding cycles. As a result, sufficient mist is introduced and also sufficient time remains for the aerosol mist to drop down and for the storage items to absorb this moisture.

When introducing the aerosol mist into the storage area 6 the time of a mist impulse and/or discharge cycle is selected such that this mist fills the storage area 6 as completely as possible without the mist escaping from the vents of the storage area 6.

The misting rate which is produced by the misting device also depends on storage area-specific influencing factors and/or fluid-specific influencing factors and/or misting device-specific influence factors. In this connection, an ambient temperature and a water temperature of the fluid provided for the misting are taken into account. In a closed storage area 6, the introduction of the aerosol mist is preferably carried out cyclically. In particular, misting rates of 0.5 g per day and per 100 cm² are introduced, wherein this is preferably carried out with a number of 15 to 20 discharge cycles having one respective mist impulse duration and/or cycle duration of between 55 seconds and 65 seconds.

Preferably, these product-specific setpoint misting rates, which are then preferably stored as reference values in the control unit, and the respective actual misting rates, which are storage item-specific, are then compared with corresponding stored reference values.

Preferably, inlet openings for introducing the aerosol mist into the storage area 6 are located in a front zone of the storage area 6 so that the accessibility and facility for cleaning is also improved thereby. These openings may be preferably positioned in the cover or the drawer of the storage area 6, so that the aerosol mist to be introduced is distributed as uniformly as possible over the bottom surface. Preferably, these ventilation openings are located in a rear zone and are thus at a distance from the mist inlet openings in the front zone.

In addition to the already-mentioned temperatures as influencing factors, it may also be provided that a misting rate drops according to a filling height of the fluid to be misted in a tank and this is compensated over time by the misting rate being adapted. This may take place via a piezo element, in particular a piezo-ceramic of the mist generator, which represents the misting device. However, in order to be able to introduce a mist quantity into the storage area 6 which is as uniform as possible, via a complete filling of the tank, i.e. up to the maximum filling height, for example, at least the mist impulse duration is shown as a function of the operating time and the filling height and the adaptation of the misting rate carried out as a function thereof. In this connection, correction factors which are stored in a memory of the control unit may be taken into account. By these correction factors, the misting rate is preferably kept in a set range, relative to one day as a time interval unit of an entire storage time, and relative to a surface, and thus a setpoint misting rate is sought. In this connection, the mist quantity discharged in the storage area 6 is produced, preferably between 0.4 g per day and per 100 cm² storage surface up to 0.6 g per day per 100 cm² storage surface.

Moreover, for adapting a current misting rate the loading of the storage area 6 and/or the volume of the storage area 6 may be taken into account as further influencing factors. The mass and/or the surface of the storage items may also be considered relative thereto.

It may also be provided that a mist impulse duration relative to the running time of the misting device is also stored in the memory of the control unit. It is then assumed that the filling state of the fluid in the tank is only altered by the misting device but not by the user as long as the tank has not been removed. If this tank has been removed for filling, then it is assumed in this controller that the user has filled up the tank up to the set level, in particular the maximum level.

For detecting the filling state of the water tank it is also possible that the filling state is detected via a sensor, for example via a capacitive sensor or via an ultrasonic measurement. Thus the misting rate may be corrected via the controller according to the filling state.

In order to take into account the influence of the ambient temperature on the temperature of the storage area 6 and thus also of the misting device, corresponding correction values or correction factors may be stored in the memory of the control unit.

The temperature may also be detected by sensor. As a result, the influence of the surface tension of the fluid on an optionally undesirable deviation of the misting rate may be partially taken into account. This surface tension, however, may also be detected by measurement technology, for example by a force measurement. Moreover, the water hardness of the fluid to be misted may also be detected and considered as influencing parameters, so that this influencing factor is also taken into account here in order to adapt the misting rate such that it is corrected within a tolerance interval around a predetermined setpoint misting rate.

Due to the water hardness, deposits may be formed on the piezo element of the misting device, which may contribute to the impairment of the mist generating rate. Therefore, it is preferably provided that this piezo element is decalcified, wherein this is indicated to a user preferably acoustically or optically via the control unit.

It may also be provided that the misting rate is influenced by altering the electrical voltage of this piezo element and in this connection an adaptation has to take place in order to be able to compensate for this alteration.

It is also possible that the frequency of the electrical operating voltage of this piezo element is altered in order to influence the aerosol droplet size and thus also to influence the misting rate. By means of this embodiment, the dropping time of these aerosol droplets may be varied and thus the distribution of the aerosol mist may be influenced.

The misting device also reduces its misting rate over its entire operating time. Thus the misting rate may be reduced in otherwise constant conditions. For example, after several 1000 operating hours, for example after 3000 operating hours, the misting rate is reduced by 30 percent. In order to take into account these misting device-specific influencing factors, and then also in order to be able to keep the actually produced misting rate at the desired setpoint misting rate, the running time of the misting device may be detected and correspondingly corrected. Correction factors of the misting rate are assigned to the running time of the misting device, for example by means of a table. Thus the running time may be stored as a number, wherein a counter unit, for example, then matches a time interval thereto of preferably one day. Depending on the status of the counter unit, the factor for the correction of the running time of the mist impulse is used in the control program for the adaptation.

In order to keep the equilibrium moisture content of the stored storage items as far as possible at the respective individual level, in terms of time the aerosol mist has to be introduced into the storage area 6 so that the moisture losses of the storage items but also the losses due to condensation on the walls, the floor and the cover or caused by opening the storage area 6 for the removal or the storage of storage items, are compensated. To this end, one or more humidity sensors may be present for controlling the mist input and which are preferably connected so that they permit sufficiently accurate information about the relative air humidity in the storage area 6. Preferably, these sensors may be arranged in the region of a door and/or in the region of an evaporator of a refrigerating circuit of the domestic refrigeration appliance and/or at a cool air inlet in the case of a no-frost appliance.

Alternatively, the mist input may be controlled according to the running time of the refrigeration compartment, for example of an evaporator or a cold air inlet, and thus also device-specific influencing factors for adapting the misting rate may be taken into account. In a so-called standby time of the compressor or a standby time of the cold air inlet, the temperature in the refrigeration compartment and thus also in the storage area rises. As a result, the air in the storage area may absorb more moisture. The relative air humidity drops. In order to counteract the drop in the relative air humidity a short mist impulse, preferably in addition to the already discharged mist impulses, may be discharged into the storage area 6. As a result, it is achieved that the relative air humidity in the storage area 6 is kept as constant as possible for each time interval of a storage time.

Preferably, it is provided that the humidity applied to the storage items is detected, wherein the mist deposit on the storage items is detected. To this end, in particular, a detection unit which operates with infrared radiation is provided. This detection unit is arranged in the domestic refrigeration appliance. The absorption ranges of water are located in the wavelength range of between 1.920 nm and 1.950 nm and/or between 1.400 nm and 1.450 nm which may then be detected by sensor. The absorption may then be taken into account as a measurement of the film of moisture on the storage items or even for determining the entire water contents of the foodstuffs and thus of the storage items, even without wetting. For establishing this the infrared source of this unit is activated and the storage items illuminated thereby. An infrared receiver of this unit detects the radiation reflected by the storage items. A comparison of this radiation without a film of moisture, which then, for example, may be stored as a reference value in the control unit, then permits information to be provided about the film of water and/or mist deposit present on the storage items.

A reflection of light in the visible spectral range is also a measurement of the wetting of the storage items by water and/or a mist deposit. In this case, a correspondingly operating light source may illuminate the storage items and a corresponding detector, for example a photodiode, detects the reflected radiation. The voltage discharged by the detector is compared with a comparison value, in particular determined from the detector voltage without the film of water. A measurement of a control variable for scattering the mist input and thus the misting rate in the storage area is also permitted thereby.

The water content may also be determined by a further alternative measuring method. This may be determined, for example, via an acoustic measuring method, by means of ultrasound signals between 20 kHz to 10 gHz or by a terahertz measuring technology. The terahertz radiation has a penetration depth in the storage items. Therefore, this radiation is better suited to determining the wetting of the storage items. In this connection, in the disclosed alternative methods it may also be provided that the stored product is identified and/or may be input in further detail in terms of its type and design, so that the measurements which are relevant thereto are more accurate and more relevant to the situation. It may also be provided that a camera is provided which permits the recording of an image relating to the contents of the storage area 6.

LIST OF REFERENCE NUMERALS

1 Domestic refrigeration appliance

2 Housing

3 Internal container

4 Internal space

5 Refrigerating circuit

6 Storage area

7 Partition

8 Partial volume

9 Drawer

10 Door

11 Humidifying device 

1-13. (canceled)
 14. A method for operating a domestic refrigeration appliance, the refrigeration appliance having an internal space formed with a separate storage area configured to receive foodstuffs to be stored therein as storage items and configured for a liquid fluid to be introduced in the storage area independently of the internal space, the method which comprises: keeping the storage items fresh in the storage area by operating the refrigeration appliance in a first operating mode and in a storage mode different from the first operating mode; in the storage mode, introducing an aerosol mist generated by a misting device of the domestic refrigeration appliance as a fluid and matching a misting rate of the aerosol mist during the storage mode to a setpoint misting rate in dependence on at least one parameter selected from the group consisting of a misting device-specific influencing parameter, a fluid-specific influencing parameter, and a storage area-specific influencing parameter.
 15. The method according to claim 14, which comprises predetermining a constant setpoint misting rate over an entire storage time period of the storage items, and adapting a current misting rate such that the entire storage time of the storage items is divided into at least two time intervals and a misting rate in a first time interval of the storage mode is within a tolerance interval of a misting rate in a second time interval of the storage mode and the misting rates of the at least two time intervals lie within a tolerance interval of the setpoint misting rate.
 16. The method according to claim 15, wherein the storage time period is at least two days and each of the first and second time intervals is one day.
 17. The method according to claim 15, which comprises setting the misting rates in the time intervals with values of between 0.4 g and 0.6 g per 100 cm² during the storage mode according to at least one misting device-specific influencing parameter and/or a fluid-specific influencing parameter.
 18. The method according to claim 17, which comprises setting the misting rates according to at least one parameter selected from the group consisting of a water hardness and a storage area-specific influencing parameter.
 19. The method according to claim 17, which comprises setting a mist quantity to between 0.4 g and 0.6 g per 100 cm², in 15 to 20 discharge cycles in the storage area with cycle times of between 55 seconds and 65 seconds, and setting a number of discharge cycles and/or a duration thereof during the storage mode according to at least one parameter selected from the group consisting of a misting device-specific influencing parameter, a fluid-specific influencing parameter, and a storage area-specific influencing parameter.
 20. The method according to claim 14, which comprises adapting the misting rate during an implementation of the storage mode to a loading quantity of the storage area with specific storage items and/or a total volume of the storage area as a storage area-specific influencing parameter.
 21. The method according to claim 14, which comprises adapting the misting rate during an implementation of the storage mode according to at least one fluid-specific influencing parameter selected from the group consisting of a temperature of the fluid to be misted, a temperature alteration of the fluid to be misted, a temperature in the surroundings of a tank comprising the fluid to be misted and a temperature alteration of a tank comprising the fluid to be misted.
 22. The method according to claim 14, which comprises adapting the misting rate during an implementation of the storage mode according to at least one fluid-specific influencing parameter selected from the group consisting of a filling height of the fluid to be misted in a tank of the domestic refrigeration appliance and a water hardness of the fluid.
 23. The method according to claim 14, which comprises adapting the misting rate during the implementation of the storage mode according to a total operating time of the misting device as a misting device-specific influencing parameter.
 24. The method according to claim 14, which comprises adapting the misting rate during the implementation of the storage mode according to a service life of a component of a refrigerating circuit of the domestic refrigerating appliance.
 25. The method according to claim 24, wherein the component is an evaporator of the domestic refrigerating appliance.
 26. The method according to claim 14, which comprises introducing the aerosol mist in accordance with a type, a quantity and a position of the storage items in the storage area, which at times are at least locally limited in a storage area zone.
 27. The method according to claim 14, which comprises, for keeping the storage items fresh in the storage area, carrying out a refreshing mode as a first operating mode, and thereby introducing the fluid into the storage area for adjusting an application of the fluid onto the storage items in the storage area according to a reduced mass of the storage items in comparison with a fresh mass thereof and, as a result, to thereby increase a mass of the storage items.
 28. A domestic refrigeration appliance, comprising: a housing having an internal space with a separate storage area configured therein for foodstuffs as storage items; a misting device for introducing a liquid fluid into said storage area independently of said internal space; and a control unit for controlling said misting device in accordance with the method accordance with claim
 14. 